U.S. Provisional Application Nos. 60/699,641, and 60/699,490, both filed Jul. 15, 2005, and U.S. Provisional Application No. 60/699,943, filed Jul. 16, 2005, are incorporated herein in their entirety by reference. U.S. Pat. No. 6,901,729 is also incorporated herein in its entirety by reference.
Vehicles, such as, but not limited to, agricultural windrowers, can utilize control algorithms for translating input signals, for instance, from operator controlled input devices such as a forward-neutral-reverse (FNR) lever, also sometimes referred to as a multi-function-handle (MFH), to systems to be controlled thereby, such as the propulsion driveline.
It is therefore desirable to have a capability to monitor the performance of such control algorithms, to ensure that the input commands are being accurately and safely translated into machine operations and movements. This can be generally referred to as propulsion system safeing. It is also desirable to have the capability to determine or sense when a controlled system, such as a propulsion driveline, is no longer tracking a reference input signal sufficiently well. A degradation in the tracking capability can occur for any of several reasons, such as an interrupted or corrupted communication path, such as due to electrical noise and/or damage to a conductive path such as a wiring harness, physical wear or damage, and the like. It is also desirable to have the ability to determine or sense when the controlled system is overshooting or undershooting a system bounds. For instance, a propulsion system may drive a vehicle such as a windrower at a speed greater than a set speed. A system can overshoot (measured system output exceeds the desired output value) or undershoot (measured system output is less than the desired output value), which may indicate that a controller for the output has become unstable. Safeing in the instance of these conditions, will provide a manner of returning to a safe mode, which can include automatically going to a neutral mode, and/or shutting down the propulsion system.
It is also desirable to have the capability for providing an automatic park brake for ensuring that when the FNR lever is moved to the neutral position, or is already in the neutral position, the windrower is prevented from moving either in the forward, or the reverse direction.